Sensor devices, such as pressure sensor devices, are widely used in many applications. For example, pressure sensor devices can be used for monitoring tire pressure in automotive tires or for monitoring air pressure in an air filter system. Acoustic sensors can be used for detecting acoustic waves or sound. Optical sensors can be used for detecting light wave or light beam. In a typical application, one or more sensor devices are usually integrated with other components in a system. To reduce the size and the cost of the system, it is highly desirable to have the sensor device(s) in a small form factor, yet reliable, package. However, this task remains challenging. For example, some existing pressure sensor devices have a pressure sensor chip mounted on a substrate and covered with a plastic lid. An epoxy sealant is applied between the substrate and the plastic lid to hold pressure therein. Such solution is not completely satisfactory for a few reasons. For example, using epoxy sealant may lead to a higher manufacturing cost due to extended assembly time and increased process complexity. In addition, epoxy sealant may fail over time.
Accordingly, improvements in the packaging of sensor devices are desired.